Method and system for automatic eyesight diagnosis

ABSTRACT

Embodiments of the invention are related to a method and a system for eyesight diagnosis. The system includes a vision test unit and a controller. The vision test unit includes at least one eye movement tracking unit configured to track the movement of a portion of the eye, at least one screen for visual stimulation and a shuttering unit configured to controllably block the field of view (FOV) of each eye separately. In some embodiments, the controller includes a processor and a non-volatile memory that store thereon instructions that when executed by the processor causes the controller to: display to a patient a first visual stimulation on the at least one screen, cause the shuttering unit to block the FOV of a first eye of the patient while unblocking the FOV of a second eye, receive a first signal indicative of the second eye movement of the patient from the at least one eye movement tracking unit and diagnose the patient&#39;s eyesight based on the received first signal.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/653,564, filed Jul. 19, 2017, now U.S. Pat. No. 9,844,317, which is acontinuation of POT International Application No. PCT/IL2016/050066,International Filing Date Jan. 20, 2016, claiming the benefit of U.S.Patent Application No. 62/105,235, filed Jan. 20, 2015, all of which arehereby incorporated by reference.

BACKGROUND OF THE INVENTION

Visual Acuity (VA) tests in humans are usually performed byprofessionals such as ophthalmologists, optometrists and in some casespublic-health nurses. Such tests require special training, specialequipment and the patient's collaboration.

In a typical VA test the professional preforming the test presentsvisual stimulations such as presenting objects or characters (e.g.numbers and letters) at various sizes presented to the patient atdecreasing size order. The patient is required to respond to thepresented visual stimulation by identifying, verbally or in any otherway (e.g., hand waving) the presented object or character. Theprofessional tests each of the patient's eyes separately, while coveringthe other eye and the patient verbally required to notice theprofessional whether he/she sees the visual stimulation presented. Amanual actuality test conducted by an optometrist that requires thepatient's active participation takes more than 10 minutes and itsaccuracy relays heavily on the response of the patient and theprofessionalism of the optometrist.

Similar approach is implemented when testing a three-dimensional (3D)vision of the patient. The patient is given polarizing glasses andpresented with a 3D visual stimulation. Here again the professionalneeds to hear the verbal response of the patient to various 3D visualstimulations in order to detect problems with the patient's 3D vision.

Tests that require a full verbal collaboration of the patient cannot beused to test or inspect infants, babies and people having difficultiesin verbal communication such as people suffering from autism. The onlyknown method of conducting VA tests in these groups is the use ofTeller-Cards (also known as Teller Visual Acuity Cards). Teller cardsare cards presenting vertical (or horizontal) black- and white strips atdifferent widths and frequencies, starting at relatively wide stripesand ending with relatively narrow strips. Specially trainedophthalmologist tracts the eye movement of the patient using a smalllamp as the patient is presented with the various Teller-cards. EachTeller card includes alternating black and white strips (either rows orcolumns) having a known/constant width alternating at a specificfrequency. The Teller cards are presented to the patient in a contrastdecreasing order starting with a card having wide strips and lowfrequency. When a patient cannot detect the contrast between the whiteand black strips (i.e., the card will look as a solid grey square), theprofessional conducting the test may notice a change in theconcentration or gazing of the patient, indicating that the patientdidn't notice the contrast presented. Teller cards are defined by anumber of Cycles Per Centimeter (CPC) from the first strip to the laststrip, presented at each cards. There are cards having 0.23, 0.32, 0.43,0.64, 0.86, 1.3, 1.6, 2.4, 3.2, 4.8, 6.5, 9.8, 13.0, 19.0, 26.0 CPC,wherein, the 0.23 CPC has the widest strips and the 26.0 CPC has thenarrowest strips. An eye of a patient having the ability to see thehighest Teller card having 26.0 CPC has 6/6 vision (e.g., that at sixmeters test distance the patient could correctly identify a letter thata ‘normal’ sighted person should see at six meters, also referred to asnormal vision). However, since the testing is done to both eyessimultaneously, the test can only give an indication that the patientmay have a vision acuity problem. Some exemplary Teller-cards areillustrated in FIGS. 1A-1D.

Prior art methods for testing eyesight require the use of dilating eyedrops that contain medication to enlarge (dilate) the pupil of the eye.There are two types of drops: one type stimulates contraction of themuscles that enlarge the pupil (such as phenylephrine); the other typerelaxes the muscles that make the pupil constrict and also relaxes themuscle that focus the lens of the eye (such as cyclopentolate). The useof such dilating eye drops is very unpleasant and leaves the patientwith blurred eyesight for couple of hours after the test.

Currently there is no reliable objective method or system for conductingacuity tests or diagnosing eyesight in general that does not relay onthe patient's collaboration.

SUMMARY

Embodiments of the invention may be related to a method and a system foreyesight diagnosis. The system may include a vision test unit and acontroller. The vision test unit may include at least one eye movementtracking unit that may be configured to track the movement of a portionof the eye, at least one screen for visual stimulation and a shutteringunit that may be configured to controllably block the field of view(FOV) of each eye separately. In some embodiments, the controller mayinclude a processor and a non-volatile memory that store thereoninstructions that when executed by the processor may cause thecontroller to: display to a patient a first visual stimulation on the atleast one screen, cause the shuttering unit to block the FOV of a firsteye of the patient while unblocking the FOV of a second eye, receive afirst signal indicative of the second eye movement of the patient fromthe at least one eye movement tracking unit and diagnose the patient'seyesight based on the received first signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter regarded as the invention is particularly pointed outand distinctly claimed in the concluding portion of the specification.The invention, however, both as to organization and method of operation,together with objects, features, and advantages thereof, may best beunderstood by reference to the following detailed description when readwith the accompanying drawings in which:

FIGS. 1A, 1B, 1C and 1D are exemplary prior art Teller cards;

FIG. 2 is a block diagram of a system for eyesight diagnosis accordingto some embodiments of the invention;

FIGS. 3A and 3B are illustrations of exemplary visual stimulationsdisplay according to some embodiments of the invention;

FIG. 4 is an image of an exemplary shuttering unit according to someembodiments of the invention; and

FIG. 5 is a flowchart of a method of eyesight diagnosis according tosome embodiments of the invention.

It will be appreciated that for simplicity and clarity of illustration,elements shown in the figures have not necessarily been drawn to scale.For example, the dimensions of some of the elements may be exaggeratedrelative to other elements for clarity. Further, where consideredappropriate, reference numerals may be repeated among the figures toindicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those skilled in the art that thepresent invention may be practiced without these specific details. Inother instances, well-known methods, procedures, and components have notbeen described in detail so as not to obscure the present invention.

Embodiments of the present invention may be related to providing asystem and method for conducting reliable tests for eyesight diagnosis(e.g., acuity test, squint detection tests, 3D vision tests etc.). Insome embodiments, using a method and a system of the invention may notrequire any cooperation or collaboration from a testee (e.g., a humanpatient been tested). Such a system may be used for testing the eyesightof infants, babies, any other patient. A system according to embodimentsof the invention may rely on objective, substantially accuratemeasurements done automatically by a computerized controllable system.

A system according to some embodiments of the invention may not rely onreceiving inputs from humans, either from a professional conducting thetest or the patient. The system may receive substantially accuratemeasurements from sensors (such as, infra-red (IR) cameras orelectrodes) and information from other controllable components (e.g., ashuttering unit that blocks the FOV of an eye) included in the system.Accordingly, since human interference is not required the test may beconducted at a very short time, for example, in less than 2 minutes oreven less than 80 seconds

An exemplary system according to embodiments of the invention may detectthe eye movement using infrared (IR) sensors. The eye movement may becaused by a controllable visual stimulation displayed to the patient ona screen, for example, a Teller card. The system may further include awearable device, such as, for example, special glasses, that enablescontrollable blocking of the Field Of View (FOV) of each eye separately.The IR sensor may be either located on the wearable device (e.g.glasses) or located at a predetermined distance from the patient's eyes,for example, near the screen presenting the visual stimuli.

Reference is made to FIG. 2 that is a block diagram of a system forautomatic eyesight diagnosis according to some embodiments of theinvention. System 200 may also be suitable for detecting severaldeviations from healthy eye sight, such as, acuity, 3D sight problems,squint or the like. System 200 may include a vision test unit 205 and acontroller 240. Vision test unit 205 may include at least one eyemovement tracking unit 210 configured to track the movement of a portionof the eye (e.g., the pupil, the iris, the muscles of the eye, or thelike), at least one visual output device, such as screen 220 for visualstimulation, and shuttering unit 230 that may be configured tocontrollably block the FOV of each eye separately. All or some elementsof vision test unit 205 may be in communication with each other and withcontroller 240. In some embodiments, system 200 may further include auser interface 250.

In some embodiments, one or more elements of system 200 may be includedin a wearable housing configured to be worn by the patient. For example,shuttering unit 220 may be included in a glass-like element. In yetanother example, eye movement tracking unit and shuttering unit 220 maybe included in the wearable housing. In some embodiments, vision testunit 205 may be included in a single housing configured to be worn bythe patient. In such an arrangement, eye movement tracking unit 210,screen 220 and shuttering unit 230 may all be embedded in a singlehousing, for example, a helmet-like housing, a hat-like housing, virtualreality glasses or the like Vision test unit 205 may be configured tocommunicate with controller 240 using a single communication system, forexample, a single USB cable to connect vision test unit 205 tocontroller 240, Bluetooth transceivers or any other wired or wirelesscommunication systems. In some embodiments, system 200 may be allincluded in a single housing configured to be worn by the patient.Controller 240 may be any processing unit that is configured to controlthe various elements of system 200. Controller 240 may include aprocessor 242 configured to execute instructions stored in a memory 244associated with processor 242. Processor 242 may include any computingplatform, for example, a Central Processing Unit (CPU) processor, a chipor any suitable computing or computational device. Memory 244 mayinclude non-transitory (non-volatile) readable medium and/ornon-transitory storage medium, such as for example a memory, a diskdrive, or a USB flash memory for storing instructions, e.g.,computer-executable instructions, which, when executed by a processor(e.g., processor 242), carry out methods disclosed herein, for example,method for diagnosing eyesight, disclosed below.

User interface 250 may be or may include input devices such as, a mouse,a keyboard, a touch screen or pad or any suitable input device that mayallow a user to communicate with controller 240. User interface 250 mayinclude a separate screen or may be in communication with screen 220 forpresenting to the user data, results, recommendations or the like.

In some embodiments, eye-movement tracking unit 210, also known in theart as “eye-tracker”, may be configured to track the movement of aportion of the eye, for example, the pupil. Unit 210 may include atleast one sensor for sensing the movement of the eye by sensing themovement of the pupil or other portions of the eye. There are somesensors that can sense the eye-movement, for example, light sensors,usually infrared, that may measure light reflected from the eye andsensed by a video camera or other optical sensor. In yet anotherexample, the eye movement can be sensed by electric potentials measuredwith electrodes placed around the eyes. The eyes are the origin of asteady electric potential field, which can also be detected in totaldarkness and if the eyes are closed. In some embodiments, eye-movementtracking unit 210 may be placed in proximity to the eye, for example, IRsensors (e.g., cameras) may be placed on glasses (or any other wearabledevice) worn by the patient, or electrodes for measuring electricpotential may be placed around the patient's eyes. In some embodiments,eye-movement tracking unit 210 may be placed at a predetermined distancefrom the eye, for example, an IR sensor may be attached to the lowerportion of screen 220 (as illustrated and discussed with respect toFIGS. 3A and 3B). Other locations may be used. Eye tracking unit 210 maysend IR signals to the eye at a frequency of 50 Hz-250 Hz, for example,230 Hz and may measure the location of the eye after each signal, forexample, by measuring the IR reflection from the pupil.

Reference is made to FIGS. 3A and 3B that are illustrations of screensfor visual stimulations according to some embodiments of the invention.

Screen 220 may be any visual display known in the art that is configuredto display a visual stimulation, for example, virtually representedTeller card 222A and/or 222B. Screen 220 may present visual stimulations222A and/or 222B to the user. Screen 220 may be a touch screen, plasmascreen, Light Emitting Diode (LED) screen, a medical grade display orthe like. Screen 220 for visual stimulation may be a screen configuredto display black and white pixels and visual stimulations 222A and/or222B may include only black and white graphical elements. The use ofblack and white visual stimulation is according to the optimal contrastsensitivity of the human eye, yet different visual stimulation may beused. Screen 220 may be configured to display visual stimulation 222Aand/or 222B to the user at an optical grade contrast, for example, theresolution of the screen must be higher than the highest Teller card26.0 CPC such that the Teller card generated on the screen may have therequired resolution.

The visual stimulation may include a visual stimulation (i.e., digitalrepresentation) of Teller-cards, different objects, animated objects(e.g., a dancing clown), 2D objects for simulating 3D vision (e.g., twosimilar objects presented to each eye at a different location), or thelike. In some embodiments, screen 220 may be in communication with userinterface 250. In other embodiments, user interface 250 may include aseparate screen.

In some embodiments, elements of eye movement tracking unit 210, forexample, sensors (e.g., IR cameras) 215, may be located in theperipheral area of screen 220, as illustrated in FIGS. 3A and 3B.

In some embodiments, vision test unit 205 may include a first screen 220for visual stimulation of the first eye and a second screen 220 forvisual stimulation of the second eye. The first and second screens 220may be included in a single housing, such as a wearable housing, forexample, in a helmet-like housing, a hat-like housing or virtual realityglasses. In some embodiments, controller 240 may be configured todisplay to the patient first visual stimulation 222A on first screen 220and display to the patient second visual stimulation 222B on the secondscreen.

Reference is made to FIG. 4 that is an illustration of shuttering unit230 according to some embodiments of the invention. Shuttering unit 230may be configured to block the FOV of each eye separately. Shutteringunit 230 may have a form of shuttering glasses, as illustrated in FIG.4, or any other wearable device, for example, a helmet, a hat or a headbend having FOV blocking elements, or the like. Shuttering unit 230 mayinclude a FOV blocking element 232, connecting elements 234 (e.g., wiresor transceivers for wireless communication) and a controlling unit 236.Controlling unit 236 may be configured to communicate with controller240, via wired or wireless communication. For example, shuttering unit230 may be in direct wired communication via a USB port included incontroller 240. In yet another example, shuttering unit 230 may includea transceiver for conducting wireless communication with controller 230,for example, via Bluetooth communication. According to some embodiments,shuttering unit 230 may be an autonomous unit in active communicationwith controller 240 to controllably block the FOV of an untested eyeduring the test of the other eye.

An exemplary shuttering unit 230 may block the FOV of each of thepatient's eyes according to instructions given to shuttering unit 230 bycontroller 240. For example, shuttering unit 230 may block the FOV ofthe right eye of the patient when eye-movement tracking unit 210 istracking the movement of the left eye of the patient. In someembodiments, shuttering unit 230 may block the FOV of the same eye whicheye-movement tracking unit 210 is tracking. In some embodiments, one ormore sensors of eye-movement tracking unit 210 may be located onshuttering unit 230, for example, two sensors (e.g., IR cameras) eachlocated on the lower portion of a shuttering unit such as shutteringglasses 230 illustrated in FIG. 4, on the right and left frames, or asingle sensor located on the bridge between the right and left screenscovering the right and left eyes, as disclosed below.

Shuttering unit 230 may include one or more FOV blocking elements 238each having an ability to block the FOV on command, for a predeterminedperiod of time, for example, 0.005 second, 0.01 second, 0.1 second, 1second, 2 seconds or the like. An exemplary FOV blocking elements 238may include one or two 3D active Liquid Crystal Display (LCD)transparent screens configured to darken thus blocking the FOV of atleast one eye of the patient. Alternatively, FOV blocking elements 238may be or may include any other elements that may block the FOV of theeye of the patient, e.g., a covers, one or more fins or the like. Theblocking frequency may be controlled to be at least, for example, 0.5Hz-200 Hz. In some embodiment, shuttering screen(s) 238 may blockElectro-Magnetic (EM) radiation in visible light spectrum from reachingthe patient's eye, thus blocking the patient's FOV, but in the same timeallowing EM radiation in the IR spectrum to reach the eye, for example,IR radiation from eye-movement tracking unit 210, located on the lowerframe of screen 220. The frame of shuttering unit 230 may be worn asregular glasses, supported by the patient's ears, may be placed on thepatient's forehead, or may be placed at any other way that may enablethe one or more FOV blocking elements included in shuttering unit 230 toblock the FOV of the patient's eyes.

In some embodiments, the frequency of the measurements made by eyetracking unit 210 (e.g., the frequencies of the IR signals sent andreceived from the eye) may be equal to or higher than the frequency ofblocking the FOV of the eye by shuttering unit 230. In some embodiments,eye tracking unit 210 and shuttering unit 230 may be controlled (e.g.,synchronized) such that for every cycle of FOV blocking of the first eyeat least one measurement of the location of the second eye may be takenby tracking unit 210.

Reference is now made to FIG. 5 which is a flowchart of a method ofautomatically diagnosing eyesight of a patient according to someembodiments of the invention. Embodiments of the method may be performedby a controller, such as, controller 240, based on instructions storedin a memory such as memory 244 and executed by processor 242.Alternatively, embodiments of the method may be performed by any othersuitable controller.

In operation 510, the method may include displaying to a patient a firstvisual stimulation (e.g., visual stimulation 222A) on at least onescreen (e.g., screen 220). The first visual stimulation may be displayedin a first location on screen 220. The first visual stimulation mayinclude a black and with image, for example, a Teller card asillustrated in FIGS. 3A and 3B. The first visual stimulation may have afirst predefined contrast sensitivity level, for example, a number ofCPC of a Teller card that is correlative to an acuity level. A contrastsensitivity level of a visual stimulation, as used herein, correspondsto the size of contrasted details (e.g., strips having either black orwhite color) of a particular visual stimulation. The size may includethe width and length of a 2D image, the width and length and height of a3D image, the size of the contrasted details within the image or thelike. For example, the contrast sensitivity of a Teller card isdetermined by the width and the density of the black and white strips.The Teller card may have a square shape having known dimensions (withrespect to the size of the screen presenting the Teller card).

In operation 520, the method may include causing a shuttering unit(e.g., shuttering unit 230) to block the FOV of a first eye of thepatient while unblocking the FOV of a second eye. Controller 240 maycontrol a first shuttering screen 238 to block the FOV of the first eye.In operation 530, the method may include receiving a first signalindicative of the second eye movement of the patient from at least oneeye movement tracking unit (e.g., tracking unit 210). The second eye maybe drawn to gaze or look at the first stimulation displayed and thismovement of the eye may be track by eye tracking unit 210. If the firststimulation has contrast sensitivity level that can be detected by theeye of the patient (e.g., the patient sees the contrasted details of thevisual stimulation) the unblocked eye of the patient may be drawn tolook at visual stimulation. Such a movement of the eye may be detectedby eye movement tracking unit 210 and sent as signal to controller 240.

In some embodiments, the method may include displaying an animated imageor any other image (e.g., dancing clown) to the patient before and/orafter displaying visual stimulation 222A or 222B. The image may bedisplayed in order to capture the attention of the patient during thetest. The image may be displayed at the center of screen 220 or in anyother location on screen 220. In some embodiments, the location of theimage may be different from the first location of first visualstimulation 222A. The image may be displaying when the FOV of both eyesis open, or when the FOV of one eye is blocked. In some embodiments,when the image disappears from screen 220 and first visual stimulation222A appear on screen 220 at a first location, the second eye of thepatient may be drawn to follow first visual stimulation 222A to thefirst location on screen 220. This movement of the second eye may bedetected by eye movement tracking unit 210.

In operation 540, some embodiments of the method may include displayingto the patient a second visual stimulation 222B on the at least onescreen 220. The second visual stimulation may have a second knowncontrast sensitivity level, for example, a known number of CPC of aTeller card that is correlative to an acuity level. The second visualstimulation may have the same contrast sensitivity level as the firstvisual stimulation or may have different one. The second visualstimulation may be located at a second location on screen 220, differentfrom the first location. In some embodiments, system 200 for eyesightdiagnosis may include two screens 220, each one placed in front of asingle eye, for example, the screens may be included in virtualreality-like glasses, and controller 240 may control each screenseparately. For example, controller 240 may display to the patient thefirst visual stimulation on first screen 220 and display to the patientthe second visual stimulation on a second screen 220. In someembodiments, controller 240 may display an image (e.g., an animatedimage) before and/or after displaying the second visual stimulation.

In operation 550, some embodiments of the method may include causing theshuttering unit (e.g., unit 230) to block the FOV of the second eye ofthe patient, while unblocking the FOV of the first eye.

As may be seen in operation 560, some embodiments of the method mayinclude receiving a second signal indicative of the first eye movementof the patient from the at least one eye movement tracking unit (e.g.,tracking unit 210). When the second visual stimulation has contrastsensitivity level that can be detected by the eye of the patient (e.g.,the patient sees the contrasted visual stimulation) the unblocked firsteye of the patient may be drawn to look at the second visualstimulation, such a fine movement of the first eye may be detected byeye movement tracking unit 210 and sent as signal to controller 240.

In operation 570, embodiments of the method may include diagnosing thepatient's eyesight based on the received first and/or second signals.Controller 240, may receive the first signal indicative of the secondeye movement of the patient caused by the presentation of the firstvisual stimulation and blocking the FOV of the first eye and may comparethe signal to a first reference signal stored in a lookup table, forexample, in a memory associated with controller 240 (e.g., memory 244).The reference signals stored in the memory may each be associated with ahealthy eye movement in response to a display of a specific visualstimulation (having a specific contrast sensitivity level and a specificlocation on the screen) of either the first or the second eyes. If thefirst visual stimulation displayed to the patient was detected by thesecond eye of the patient (the patient successfully noticed the visualstimulation presented on the screen) and a corresponding movement wasdetected by the eye tracking unit, the signal received may be comparedto the stored reference signal. If the comparison yields that thesignals are substantially the same, controller 240 may diagnose that thesecond eye of the patient can see the first visual stimulation. If thereceived signal is substantially different from the stored referencesignal, or that no significant movement of the eye was detected,controller 240 may diagnose that the second eye of the patient may havean acute problem. The diagnosed problem may be correlated to thespecific contrast sensitivity level (e.g., acuity level) of the firstvisual stimulation.

In some embodiments, the controller may perform a similar diagnosis tothe second signal indicative of the first eye movement of the patient.The second signal may be received during the presentation of the secondvisual stimulation and blocking the FOV of the second eye. The secondsignal may be compared to a second reference signal similarly to theabove. In some embodiments, the reference signals may be received fromprevious tests conducted on healthy testees, may be calculated using acomputer simulation, stored for a specific patient in the past tests orthe like.

In some embodiments, the method may further include calibration of thesystem. A plurality of animated objects (e.g., moving dots) may bepresented to the patient on screen 220. Tracking unit 210 may track themovement of both the right and left eyes, looking for example, for IRreflections to determine the location of each pupil with respect totracking unit 210. The calibration process may be conducted beforeoperation 510 or at any point during the test if necessary.

In some embodiments, controller 240 may perform and/or repeat operations510-570 at any order. In some embodiments, controller 240 may displayvarious visual stimulations according to a predetermined sequence, forexample, display some of the Teller cards from the 0.5 CPD to the 32 CPDor objects in a decreasing size order. Controller 240 may be configuredto correlate each of the received signals indicative of the eye movementwith the specific visual stimulation that was presented to the patientduring measurement of the eye movement.

In some embodiments, system 100 may measure phoria (e.g., the centralfocal point of each eye). The system may calculate the gazing location,which is the point on screen 220 to which the pupil of each eye islooking when the FOV of one eye is blocked by unit 230, with respect tothe location of a visual stimulation presented on screen 220. For apatient having a healthy eye sight the gazing location and the locationof the visual stimulation (e.g., a visual stimulation having a shape ofa small circle) may be substantially the same. When the gazing locationand the location of the visual stimulation are not the same, controller240 may calculate the distance between the gazing location and thelocation of the visual stimulation. Knowing the distance of screen 220from the patient's eyes, controller 240 may calculate the phoria level(e.g., squint) of each eye, for example, if the measured distancebetween the gazing location and the location of the visual stimulationis 4 cm (measured in number of pixels on screen 220) and the distancebetween screen 220 and the patient's eyes is 50 cm, the measured phoriamay be 8 cm/1 meter (also known in the art as 8ESO).

In some embodiments, system 100 may diagnose Amblyopia problems. Inpatient suffering from Amblyopia vision loss occurs because nervepathways between the brain and the eye aren't properly stimulatedcausing the brain to ignore stimulation from one (and sometimes evenboth) of the eyes. In some embodiments, controller 240 may be configuredto present to each eye a specific visual stimulation at a specificlocation on the screen and compare between the gazing directions of botheyes looking simultaneously at the same visual stimulation, usingtracking unit 210. For example, a one year old baby with healthy eyesight may have the ability to see the resolution of a Teller card having13 CPC in both eyes in order to be diagnosed as one not having anAmblyopia problem. At age 4 and above healthy eyesight of a patient maybe determined as having the ability to see the resolution of a Tellercard having 26 CPC in both eyes. In some embodiments, the specificlocation may be in the middle of the screen and the screen may be placedat a distance of 55-65 cm. from the patient's eyes.

In some embodiments, system 100 may diagnose 3D vision problems of thepatient. Controller 240 may be configured to alternately display onscreen 220 a first and a second identical 2D visual stimulations locatedat a known distance from each other. During the displaying of the first2D visual stimulation for example, on the right side of screen 220,controller 240 may, cause shuttering unit 230 to block the FOV of afirst eye (e.g., the left eye) and vice versa. By alternating thedisplaying of the first and second 2D visual stimulations andcorrespondingly blocking of the FOV of the first and second eyes, system100 may cause the patient to see a 3D image. The alternate displaying ofthe visual stimulations and the blocking of the FOV of the right andleft eyes may be conducted at the same frequency, for example, at afrequency of 120 Hz.

Controller 240 may receive from tracking unit 210 signals indicative ofthe movement of both the left and right eyes during the presentation ofthe alternating first and second visual stimulations. Eye tracking unit210 may detect if the patient's eyes are gazing to the same location(e.g., a point located between the first and second 2D visualstimulations), which means that the patient's brain is creating a 3Dobject from the alternating 2D visual stimulations. If the patient'seyes are not gazing to the same location, the controller may concludethat the patient's brain didn't create the 3D object, thus may diagnosea problem in the 3D vision of the patient.

According to some embodiments, controller 240 may select the distancebetween the first and the second visual stimulation according tocharacteristics of the tested patient, a predetermined program selectedfor the particular patient (e.g., patients at different ages may beexpected to create 3D object from 2D images placed at a differentminimal distances). According to some embodiments controller 240 maychange the distance between the first and the second visual stimulationduring the test in order to diagnose the 3D vision of the patient. Thecloser the first and the second visual stimulations that caused thepatient's eyes to gaze to the same direction, the better is thepatient's 3D vision.

In some embodiments, system 100 may diagnose pathologies in thepatient's eyes. For example, system 100 may further include an opticalcamera and a source of bright light beam (e.g., a Retinoscope) thatsends to the eyes strong bright light beam focused towards the pupil(e.g., a light flash). The camera may detect if the reflections from thepupil of the eyes have different wavelengths (e.g., colors). Change inthe color of the reflections (e.g., from red to white) may be indicativeof a pathology in the eye (e.g., a tumor). In yet another example,system 100 may measure the diameter of each pupil based on signalsreceived from eye tracking unit 210. A difference in the diameterbetween the right and left eyes may further indicate a suspectedpathology in at least one of the eyes. In yet another example, the sizeand shape of the pupil of each eye may be measured by system 100 basedon signals received from eye tracking unit 210. If one of the pupils isnot a complete circle it may indicate that the patient's suffers from aneyelid drop.

The following are some exemplary processes for detecting deviation fromhealthy eye behavior according to some embodiments of the invention. Theprocesses may be performed using system 200.

Measuring Phoria—The Central Focal Point of Each Eye.

-   -   1) Controller 240 may display for example, an animated object at        the center of screen 220.    -   2) Shuttering unit 230 may block the FOV of the right eye for 2        seconds, during which eye-movement tracking unit 210 may tract        the location of the right eye pupil (the blocked eye) and the        gazing direction of the pupil of the left eye towards the        animated object.    -   3) Shuttering unit 230 may unblock the FOV of both eyes for 2        seconds while measuring the movements of both the left and right        eyes.    -   4) Shuttering unit 230 may block the FOV of the left eye for 2        seconds, during which eye-movement tracking unit 210 may tract        the location of the pupil of the left eye and the gazing        direction of the pupil of the right eye towards the animated        object.    -   5) Repeating the stages until detecting a focal point of each        eye.

Measuring Eye-Acuity May Include:

-   -   1) Conducting a calibration process by displaying 6 moving        points to the patient and detecting by eye tracking unit 210 the        location of the pupil of each eye.    -   2) Presenting to the patient an animated image for grabbing the        attention of the patient.

During steps 3-16 eye movement tracking unit 210 may track and recordsthe movement of each of the left and right eyes.

-   -   3) Presenting a 3.2 CPC Teller card on screen 220 at a first        location while blocking the FOV of the right eye for 4 seconds.    -   4) Presenting a 3.2 CPC Teller card on screen 220 at a first        location while blocking the FOV of the left eye for 4 seconds.    -   5) Presenting an animated image when the FOV of both eyes is        unblocked.    -   6) Presenting a 6.5 CPC Teller card on screen 220 at a first        location while blocking the FOV of the right eye for 4 seconds.    -   7) Presenting a 6.5 CPC Teller card on screen 220 at a second        location while blocking the FOV of the right eye for 4 seconds.    -   8) Presenting an animated image when the FOV of both eyes is        unblocked.    -   9) Presenting a 6.5 CPC Teller card on screen 220 at the first        location while blocking the FOV of the left eye for 4 seconds.    -   10) Presenting a 6.5 CPC Teller card on screen 220 at the second        location while blocking the FOV of the left eye for 4 seconds.    -   11) Presenting an animated image when the FOV of both eyes is        unblocked.    -   12) Presenting a 13 CPC Teller card on screen 220 at a first        location while blocking the FOV of the right eye for 4 seconds.    -   13) Presenting a 13 CPC Teller card on screen 220 at a second        location while blocking the FOV of the right eye for 4 seconds.    -   14) Presenting an animated image when the FOV of both eyes is        unblocked.    -   15) Presenting a 13 CPC Teller card on screen 220 at the first        location while blocking the FOV of the left eye for 4 seconds.    -   16) Presenting a 13 CPC Teller card on screen 220 at the second        location while blocking the FOV of the left eye for 4 seconds.    -   17) Determining which of the presented Teller card was detected        by each of the eyes.    -   18) Diagnosing the acuity based of the determined.

Measuring 3D Vision May Include:

Controlling shuttering unit 230 to alternately block the FOV of the leftand right eyes at a frequency of 120 Hz.

-   -   1) Presenting on screen 220 a first visual stimulation while        blocking the FOV the right eye;    -   2) Presenting on screen 220 a second visual stimulation,        identical to the first visual stimulation at a known distance to        right from the first visual stimulation while blocking the FOV        the left eye;    -   3) Alternately repeating steps 1) and 2) while tracking using        tracking unit 210 the gazing direction of both the right and        left eyes;    -   4) Determining if both the left and right eyes are gazing        (looking) at substantially the same location (e.g., point on        screen) to determine a 3D vision.

While certain features of the invention have been illustrated anddescribed herein, many modifications, substitutions, changes, andequivalents will now occur to those of ordinary skill in the art. It is,therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the true spiritof the invention.

The invention claimed is:
 1. A vision test unit for eyesight diagnosis,comprising: at least one eye movement tracking unit configured to trackthe movement of a portion of the eye; at least one screen forcontrollably presenting visual stimulations for each eye separately; ashuttering unit configured to controllably block the field of view (FOV)of each eye separately; and a wearable housing for housing the at leastone eye movement tracking unit, the at least one screen and theshuttering unit.
 2. The vision test unit of claim 1, further comprising:a communication unit; and a controller configured to: display to apatient a first visual stimulation on the at least one screen; cause theshuttering unit to block the FOV of a first eye of the patient whileunblocking the FOV of a second eye; receive a first signal indicative ofthe second eye movement of the patient from the at least one eyemovement tracking unit; and diagnose the patient's eyesight based on thereceived first signal.
 3. The vision test unit of claim 2, wherein thecontroller is further configured to: display to the patient a secondvisual stimulation on the at least one screen; cause the shuttering unitto block the FOV of the second eye of the patient, while unblocking theFOV of the first eye; receive a second signal indicative of the firsteye movement of the patient from the at least one eye movement trackingunit; and diagnose the patient's eyesight based on the received secondsignal.
 4. The vision test unit of claim 3, wherein the first visualstimulation has a first contrast sensitivity level and the second visualstimulation has a second contrast sensitivity level, and wherein thefirst contrast sensitivity level is different than the second contrastsensitivity level.
 5. The vision test unit of claim 2, wherein thecontroller is configured to: display the first visual stimulation in afirst location on the at least one screen; and display the second visualstimulation in a second location on the at least one screen, differentfrom the first location.
 6. The vision test unit of claim 1, furthercomprising: a first screen for controllably presenting a visualstimulation to the first eye; and a second screen for controllablypresenting a visual stimulation to the second eye, wherein the firstscreen and second screen are held by the wearable housing.
 7. The visiontest unit of claim 1, wherein the signal indicative of the eye movementis received from a camera included in the at least one eye movementtracking unit, configured to detect infrared reflections from the pupilof the eye.
 8. The vision test unit of claim 1, wherein the signalindicative of the eye movement is received from at least one electrodeplaced close to the eye.
 9. The vision test unit of claim 1, wherein theat least one screen for visual stimulation is a screen configured todisplay black and white pixels.
 10. The vision test unit of claim 1,wherein sensors included in the at least one eye movement tracking unitare located on the peripheral area of the at least one screen.
 11. Thevision test unit of claim 1, wherein the wearable housing is a virtualreality-like glasses.
 12. A vision test unit for eyesight diagnosis,comprising: at least one eye movement tracking unit configured to trackthe movement of a portion of the eye; a first screen for controllablypresenting a visual stimulation to a first eye; a second screen forcontrollably presenting a visual stimulation to a second eye; and awearable housing for housing the at least one eye movement trackingunit, the first screen and the second screen.
 13. The vision test unitof claim 12, further comprising: a shuttering unit, included in thewearable housing, and configured to controllably block the field of view(FOV) of each eye separately.
 14. The vision test unit of claim 12,further comprising: a controller configured to: display to a patient afirst visual stimulation on the first screen; receive a first signalindicative of the first eye movement of the patient from the at leastone eye movement tracking unit; display to the patient a second visualstimulation on the second screen; receive a second signal indicative ofthe second eye movement of the patient from the at least one eyemovement tracking unit; and diagnose the patient's eyesight based on thereceived first and second signals.
 15. The vision test unit of claim 14,wherein the first visual stimulation has a first contrast sensitivitylevel and the second visual stimulation has a second contrastsensitivity level, and wherein the first contrast sensitivity level isdifferent than the second contrast sensitivity level.
 16. The visiontest unit of claim 12, wherein sensors included in the at least one eyemovement tracking unit are located on the peripheral area of the screen.17. The vision test unit of claim 12, wherein the signal indicative ofthe eye movement is received from a camera included in the at least oneeye movement tracking unit, configured to detect infrared reflectionsfrom the pupil of the eye.
 18. The vision test unit of claim 12, whereinthe signal indicative of the eye movement is received from at least oneelectrode placed close to the eye.
 19. The vision test unit of claim 12,wherein the at least one screen for visual stimulation is a screenconfigured to display black and white pixels.
 20. The vision test unitof claim 12, wherein the wearable housing is a virtual reality-likeglasses.
 21. A system for eyesight diagnosis, comprising: a vision testunit, comprising: at least one eye movement tracking unit configured totrack the movement of a portion of the eye; at least one screen forvisual stimulation; and a shuttering unit configured to controllablyblock the field of view (FOV) of each eye separately; and a controllerconfigured to: a. display to a patient a first visual stimulation havinga first contrast sensitivity level on the at least one screen; b. causethe shuttering unit to block the FOV of a first eye of the patient whileunblocking the FOV of a second eye; c. receive a first signal indicativeof the second eye movement of the patient from the at least one eyemovement tracking unit; d. display to the patient a second visualstimulation having a contrast sensitivity level on the at least onescreen, wherein the first contrast sensitivity level is different thanthe second contrast sensitivity level; e. cause the shuttering unit toblock the FOV of the second eye of the patient, while unblocking the FOVof the first eye; f. receive a second signal indicative of the first eyemovement of the patient from the at least one eye movement trackingunit; g. diagnose the patient's eyesight based on the received firstsignal and second signal.